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Application Protocols
Application layer protocols provide network services to user applications such as web browsers and e-mail programs. Explore some of the more common Internet protocols in Figure 2, the Application 

layer, to learn more about the protocols that operate in this layer.

Transport Protocols
Transport layer protocols provide end-to-end management of the data. One of the functions of these protocols is to divide the data into manageable segments for easier transport across the network. Explore each of the protocols in Figure 3, the Transport layer, to learn more about the protocols that operate in this layer.

Internet Protocols
Internet layer protocols operate in the third layer from the top in the TCP/IP model. These protocols are used to provide connectivity between hosts in the network. Explore each of the protocols in Figure 4, the Internet layer, to learn more about the protocols that operate in this layer.

Network Access Protocols
Network Access layer protocols describe the standards that hosts use to access the physical media. The IEEE 802.3 Ethernet standards and technologies, such as CSMA/CD and 10BASE-T are defined in this layer.

Wi-Fi (802.11)
802.11	bandwidth	frequency	Approx. Year
A	54mbps	5Ghz	1999
B	11mbps	2.4Ghz	2001
G	54mbps	2.5Ghz	2006
N	540mbps	2.4ghz/5Ghz	2009

there are three types of different networks: LAN, WAN, WLAN

LAN:Stands for Local Area Network. A LAN describes connected devices under the same network, LAN’s are usually found in small offices, Schools and sometimes can be found at home.

Lan devices: Computers,printers, wireless, cables (media) switches, hub, router and severs.

WAN: stands for Wireless Area Network.  Are networks that connect LAN networks in different places and countries, for example, the internet is a massive WAN, the internet is made up of lots of connected LAN’s.

WLAN: Stands for Wireless local area network. Wireless devices connect to access points in specific areas. the range of a typical WLAN is around 30M indoors.

Peer to peer network: is a network where there is no administrator, it is all user contributed, and it cannot be shut down, like certain programmes such as youtube and limewire.

Bandwidth: Bandwidth is the amount of data that can be sent over a period of time. Bandwidth is usually measured in bits per second (bps).Imagine a motorway with cars on it, obviously the wider the motorway, the more cars can travel on it at one time, so therefore cars can get to their destinations quicker. So think of that, but in computer terms, the more bandwidth, the more information can be transferred within that period of time.

IP addressing: an IP address is used to identify your computer/device on a network. your computer gets an IP address when it first joins this network. Each device must have a unique address.

DHCP:Automatically gives a device an IP address automatically when it joins the network for the first time.

ICMP: (Internet Control Message Protocol) , is used by devices on a network to send error and control messages to computers and servers.

Hubs: is a device that extends the range on a network, it does this by recieving data on one port and then sending it to all other ports.

Bridges and Switches: this is were files are broken up into packets, then they are transmitted over a network, this allows for error checking and asier retransmission if the packet is lost or corrupted.

Routers: are devices the connect entire netowrks to eachother. Routers use use IP addressess to send frames (packets and address information)to eachother

WAP: (Wireless Access Points) Provide network access to wireless devices (laptops Iphones e.c.t)

Multipurpose devices: Are network devices that perform more than one function, it is cheaper and doenst take up as much room as buying seperate devices.

Twisted pair (Media): is a type of copper cabling that is used for telephones.and most Ethernet networks. the twisted pair is designed to provide protection agaisnt crosstalk. (noise generated  by adjacent pairs of wires in the cable.

unsheilded Twisted Pairs: Cable that has two of four pairs of wires, this relies totally on cancellation effect, produced by the twisted wire pairs that limits signal caused by EMI (electromagnetic interface.)

Sheilded Twister pair: Each pair of wires is wrapped in a metalic foil, to better sheild the wires from noise.

Fiber Optic: a glass or plastic conductor that transmits information using light. Because it is made of either plastic or glass it is not affected by EMI. this means that fibre optic can deliver a clearer signals that are clearer, can go further and have greater bandwidth.

There are 5 LAN topoligies:

• bus
• ring
• star
• extended star
• mesh

Ethernet Standards: 802.11a, data rates of upto 54Mbps

802.11b, data rsates of upto 11Mbps

802.11g: maximum speeds of 54Mbps

802.11n, theoretical bandwidth of 540 Mbps

OSI Model: is a standard

Extended Star

A peer-to-peer network allows two or more PCs to pool their resources together. Individual resources like disk drives, CD-ROM drives, and even printers are transformed into shared, collective resources that are accessible from every PC.

Unlike client-server networks, where network information is stored on a centralized file server PC and made available to tens, hundreds, or thousands client PCs, the information stored across peer-to-peer networks is uniquely decentralized. Because peer-to-peer PCs have their own hard disk drives that are accessible by all computers, each PC acts as both a client (information requestor) and a server (information provider). In the diagram below, three peer-to-peer workstations are shown. Although not capable of handling the same amount of information flow that a client-server network might, all three computers can communicate directly with each other and share one another’s resources.

A peer-to-peer network can be built with either 10BaseT cabling and a hub or with a thin coax backbone. 10BaseT is best for small workgroups of 16 or fewer users that do not span long distances, or for workgroups that have one or more portable computers that may be disconnected from the network from time to time.